Summary

It is necessary to clarify the electrical requirements for surge protective devices (SPDs) and surge protective components (SPCs) in order to realize both the resistibility and safety of telecommunication systems. Recommendation ITU-T K.143 analyses the influence on human safety of lightning measures bridging across insulation in equipment by surge suppressors. It provides guidance for the design of lightning protection and requirements on surge suppressor in equipment from the human safety standpoint. Requirements for SPDs/SPCs in multiservice surge protective devices external to the equipment and SPDs installed on lines in a building lie outside the scope of this Recommendation.